Butadiene is an important basic chemical substance and is used as an intermediate for numerous petrochemicals such as synthetic rubber and electronic materials. In addition, butadiene is the most important basic fraction in the petrochemical market, and demand and value thereof are gradually increasing. Examples of butadiene preparation methods include naphtha cracking, direct dehydrogenation of normal-butene (n-butene), and oxidative dehydrogenation of normal-butene (n-butene).
Thereamong, oxidative dehydrogenation of butene is a reaction, in which butene and oxygen react with each other in the presence of a metal oxide catalyst to produce 1,3-butadiene and water. Since the produced water is stable, the reaction is thermodynamically very advantageous. In addition, since oxidative dehydrogenation of butene is an exothermic reaction unlike direct dehydrogenation of butene, 1,3-butadiene may be generated in a high yield even at a low reaction temperature as compared with direct dehydrogenation of butene, and additional heat supply is not required. Thus, oxidative dehydrogenation of butene may be an effective production process to meet demand for 1,3-butadiene.
However, in an oxidative dehydrogenation reactor system, it is often necessary to stop operation of a reaction process for various reasons. When the operation is stopped and then restarted, a catalyst is reused, in which case reproducibility of catalyst activity should be ensured to reduce cost and time.
Therefore, there is a need for a method that can reproduce the existing catalytic activity when reaction is terminated and then restarted.